Furnace



Oct. 30, 1934. H, slNGER 1,979,083

' FURNACE Filed July 27, 1933 H .I. H to 20 O I c? w 2? W: 18 EE 2 g 1;. 1 ii Inventor- Z Harms Singe LIL/h1g1 1 7Q Attornek" I heat-transmitting medium,

Patented Oct. 30, 1934 UNITED STATES PATENT OFFICE FURNACE New York Application July 27, 1933, Serial No. 682,493 In Germany August 13, 1932 Claims.

heat from the storage medium to a heatdistributing system such that the transfer of heat can be started, stopped, and the rate of transfer controlled most effectively.

It has already been proposed to install heatdistributing coils or some other tube heating system in the storage material of accumulator furnaces which coils or tubes contain a heat-distributing medium which is caused to circulate and which delivers up its heat by means of radiators or the like to the rooms to be heated. In almost every case, the heat-distributing medium employed is water, the boiling point of which, as is well known, lies at approximately 100 C. In order to avoid dangerous pressures in the piping which may arise if the circulation of the water is stopped by means of the cooks installed in the piping, the storage material must not be heated to such a high temperature that the water in the immediately adjoining heating coils is caused to boil. Furthermore in most installations the necessity arises for providing a comparatively large quantity of storage material in order that the desired quantity of heat may be accumulated.

Therefore a special object of the present invention is to improve the construction of the accumulator furnace so that the storage material may be heated to higher temperatures than 100 C., in order to be able to use a smaller quantity of storage material and obtain the same amount of accumulated heat. With the high temperature storage material in the furnace, the transmission of heat from the storage material to the heating coil or coils or the like can be regu- 45 lated most effectively in accordance with the present invention.

In the preferred embodiment of the invention the heat-distributing coils or tubes are arranged in the furnace in a passage which adjoins the heat storage material in sections. This passage contains a moving heat-transmitting medium serving to transmit the heat from the storage material to the distributing medium such as water contained in the heating coil. For this air, hydrogen or other fluid substances are suitable. The transmitting medium is maintained in circulation either by convection currents or artificially. Regulating valves are inserted in the passage in the furnace which enable the cross-section of the latter to be altered. By this means it is possible to start, stop, or vary the circulation of the transmitting medium and thus effectively regulate the heat given up by the storage material to the heat-distributing coil.

One method of carrying out the invention is shown in the drawing, Fig. 1 being a longitudinal section of the improved accumulator furnace; Fig. 2 a cross-section of the furnace on the line 2-2 and Fig. 3 a modification of the heat transfer control.

The furnace consists of the casing 10 which is constructed so as to serve as a heat-conserving casing. In the interior of the casing, the heat storage element 11 consisting of a mixture of iron and aluminum chlorides, or other suitable material having a high thermal capacity, is placed.

The mixture in question preferably consists of aluminum chloride, sodium chloride and iron chloride which are mixed in the proportion of 0 about 613:1. Such a mixture melts at about 60 C. and can be heated far above 1000 C. without decomposition. In this way it is possible to store up large amounts of heat in a relatively small space. The heating must, of course, take 5 place with the air excluded.

It may be pointed out that other suitable mixtures may be used with the present invention which consists of the utilization of high storage temperatures and the means necessary therefor. Therefore the above salt mixture is mentioned only as an illustration for carrying out the invention whereas the invention can be used with other heat storage mixtures having high thermal capacity.

One or more electric heater windings 12 are embedded in this storage material. This heat accumulator element is provided with a large number of vertically disposed passages 13 connected in parallel to one another. These passages 13 are preferably located in concentric groups, as shown in Fig. 2, with the convolutions of the heater windings disposed between said groups of the passages to facilitate uniform heating of the heat storage material. The storage 5 element ll is located in one leg of the annular passage 14 formed inside of casing 10. In the other leg of this passage 14 the heat-distributing coil 15 containing a heat-distributing medium such as water is arranged. The coil 15 is sepaill rated from the heated storage element 11 by a heat-protecting core 16. It will be understood that distributing coil 15 is connected by the pipes 17 to the radiators installed in the rooms to be heated.

The annular passage 14 of the furnace is entirely closed and contains a heat transfer medium such as air, hydrogen, mercury or the like which may be heated to a high temperature without becoming unstable or developing excessive pressures. Communication between the legs of the annular passage 14 is controlled by regulating valves 18 which are inserted in the top and bottom of the passage between the "heat storage element 11 and the heat-distributing coil 15, the control adjustments preferably being made at these points. The piping 17 in Whichthe heated water is led from the heating coil 15'to'the radiators' is provided with a temperature-responsive regulator 19 which functions to adjust the valves 18in accordance with the temperature of the waterorthe like leaving the heating coil 15 by a lever mechanism 20. The valves 18 may beheld clo-sedindependen-tlyof regulator 19 by meansof the cam 21. Inthis .way the temperature regulator-may becut out. If desired, the regulator 19 may be-made directly-responsive to the temperature'of the room as indicated in Fig. 3.

The procedure when charging and discharging the accumulator furnace is as follows: When no heat is needed in the radiators and the accumulator element 11 has to be charged, the valves 18 are closed by turning the cam 21. The storage material 11 is then heated up by connecting the heater winding 12 to the electric supply network. The heat thus produced in :element 11 tendsto drive the liquid or gaseousmedium contained in the passage 14 upwards and setitin circulation, which isprevented however by the closed control valves .18. Wh'en the temperature of the storage material llhas risen to the desired value, the .camZl is turned from'the dotted position to the position shown .in full lines and thus releases the temperature regulator l9'which then opens the valves 18 .in case the temperature in the heat-distributing piping is comparatively low. There isznow-xnothing'further to oppose the circulation of themediumcontained in the passages 13 and 14. Thus, in accordance :withthe driving force exerted by the accumulator :heatin the example shown, it flows inwan' anti-clockwise direction from the passages 13 upwards, next flowing-along the heating coil 15 whereby it .is

cooled, and thenreturns :around through the :pas-

sages 13 once more from bel'owwhere it i'siheated up again. p

To enableall parts of the heating coil 15 ,to

have an equally good heat absorption, a spiral of the passage 14 at these points. In this way Y the rate of circulation of the medium contained in the passage 14 which transmits the heat absorbed in thenpassages .13 to the heating coil :15 will be. prevented more -or less and consequently the transmission :of heat from storage-element '11 to the heating "coil 15 -will--be more -or lessrecourse also take place with the temperature regulator in action, that is to say, with the regulating valves 18 open.

The circulating heat-transmitting medium must not be such as to decompose in the passages 13 and 14 of the accumulator furnace atthe high temperature to which the element 11 reaches. Also when a liquid is employed, it

-.must not be such as to boil at these tempera- -=tures.

The circulation of the transmitting medium in the accumulator passage 14 may be maintained-artificially by means of a fan orpump 22 driven-by amotor 23 as shown -in.Fig. 3. In this case the temperature regulator '19. is responsive to room temperatures and isallowedto regulate the speed of the motor .23 bymeansofaspeedililil regulator 24 in such away that the desired temperature of :theroom is maintained approximately constant. The fan is preferably installed at one side of the valve 18 in the passage 14 as shown.

What I claim as new and desireltosecure by Letters Patent. of the United Statesis:

1. An accumulator furnace comprising a heatinsulating casing having an annular closed passage for containing a ,fluid heattransfer; medium therein: a high ,temperatureheat storage element located in one portion of said'passage, al'heatdistributing element located in another portion of "said passage, and means for regulating the circulation of the fluid heat transfer medium- .in said passage including a :pair of valves ill-said apassage disposed one'on each'side of said-storage .element, and means for simultaneously -,op- *erating "said valves to close the passage .011 both sides of said heatistor-age element.

"2. accumulator furnacezcomprising a .heatinsuiating casing having a closed :annular :passage formed therein for containingfa fluid heat transfer medium, a :heat storage element includingxa mass-of high temperature capacity'salt 119,5 mixture :located in one portion :of saidt'passage :and havingia plurality of smaller. passagestfor the circulation of said heat transfenmediumztherethrough, means for imparting heat to saiduelementzincluding an electric ,heatingccoilrembe'dded said mixture, 2, heat absorbing and :distrihut- .in'g :element located in another portion tor .isaid passage, and adjustable valve means Ilocated in said :passagebetween saidstorage element and said .heat absorbing :and :rlistributing elementijgg; forrregulating the rate of ciroulationvofszthefluid heat transfer me'diiuni'inzsaid passage.

3. An accumulator furnace vcomprising-a heat- -insulating casing having aclosed areentrant pas- -'sageformed therein, aheat zstorage elementsincluding a high temperature capacityesalt mixture ilocate'dzin :one portion of said passage and :hav- Ling: a plurality of concentric groups :of smaller .ipassages extending therethroughgmeans fnrzuniformly heating saidheat storage :element includ- 531.15 ing an electric coil having its convolutions embedded inx-said mixtu-re concentrically with'zsaid *egroups or l-small passages, :a .heat :absonbingsand udistributingelementlocated in anotheriportionrof said reentrant passage, :a slow utemperaturetzfluidi lgq heat transfer medium adapted to circulate around said reentrant passage, and means including valves for starting and stopping and regulating the rate of circulation of said fluid heat transfer medium.

4. An accumulator furnace comprising a heatinsulating casing having an annular closed passage formed therein, a container having a high temperature capacity heat storage salt mixture therein filling one portion of said passage and having a plurality of smaller passages extending therethrough, means for heating said mixture including an electric coil embedded therein, a heat absorbing and distributing water coil located in another portion of said passage, a low temperature fluid heat transfer medium adapted to circulate in said annular closed passage and through said plurality of smaller passages, means for forcing circulation of said heat transfer medium, valve means located in said passage for stopping circulation of said heat transfer medium, and temperature responsive means for controlling said forced circulation means and said valve means.

5. An accumulator furnace comprising a heatinsulating casing having an annular closed fluidtight passage formed therein, a container filling one portion of said annular passage and having a high temperature heat storage salt mixture therein with a plurality of uniformly distributed smaller passages extending through said container and said mixture, means for heating said mixture including a plurality of electrical coils embedded therein and disposed between groups of said smaller passages, a water heating coil located in another portion of said annular passage, a low temperature fluid heat transfer medium adapted to circulate in said closed annular passage and through said smaller passages to transfer the heat from said storage mixture to said water coil, an impeller pump for circulating said heat transfer medium, valve means for closing said annular passage to stop circulation of said heat transfer medium, and thermostatic means for controlling the operation of said valve means and said motor driven pump.

HANN S SINGER. 

